Flame protection for trolley locomotives in underground mines



July 3, 1956 c. w. HoEvELs l 2,753,002

FLAME PROTECTION FOR TROLLEY LOcOMOTIvEs IN UNDERGROUND MINES Filed NOV. 18, 1955 CARL WERNER HoevLs United States Patent-O FLAME PROTECTION FOR TROLLEY LOCOMO- TN ES IN UNDERGROUND MlNES Carl W. Hoevels, Gelsenkirchen-Buer, Germany Application November 18, 1953, Serial No. 392,843

4 Claims. (Cl. 169-1) This invention relates to means for the fire damp protection of overhead wire locomotives used in the operation of coal mines.

In the operation of underground coalV mines the overhead or trolley wire locomotives have proven to be a highly economical transport means. The use of these overhead wire locomotives is, however, greatly restricted, since it has hitherto not been possible to render these locomotives iire damp safe.

No diculty prevails in making electromotors, control contacts, switch levers, cable contacts and other parts of the underground mining machine tire damp proof. However, by the current supply and particularly in the overhead lines connecting the current supply Wire and the contact brushes sparks are created which are adapted to ignite the fire damp mixtures which collect in the upper and particularly the ceiling portion of the mining tunnels. Sparks rnay also be created between the wheels of the coal transporting cars and the current return lines. Since the re damps due to their small specific gravity, are mainly produced in the upper portion of the coal mines and may form explosive gas mixture, the sparks created between the trolley wire and the contact brushes prevail in a particularly imperilled zone.

Suggestions have been made to remove the current supply wire from this zone and to shift them to a region near to the floor of the coal mine. This measure is not applicable to underground mine activities in View of the increased danger of the production of contacts and the operative diliiculties arising at crossings, junctions, switches and terminals.

It is the foremost object of the invention to eliminate the above referred to ditiiculties and to produce a safe and interruption-free performance of underground train service.

It is another object of the invention to eliminate the danger of lire damp ignition.

It is also an object of the invention to restrict the creation of sparks to the spaces where non-explosive gas mixtures prevail.

Suggestions have been already made to equip overhead wire locomotives with tanks containing compressed air and to blow the air from these tanks into the danger areas located between the Contact brushes and the current supply wire. These tanks, however, greatly reduce the operating space of the locomotives, since compressed air can only be stored at a limited rate; consequently the tanks must be often recharged.

The invention eliminates these dificulties.

In conformity therewith re damp free air is sucked from the mine shaft bottom and conducted by a ventilator and the like transporting means to the brush or slide contacts by means of tubes, rubber hose and the like. This air transport is particularly effective if the trolley wire is located in an upwardly closed and downwardly open trough-shaped cover; in this manner the fresh air supply is concentrated at the spot where the formation of sparks may take place.

Moreover, the danger of tire damp formation is also eliminated by the invention in those cases where in the vicinity of the mine level or bottom explosive gases have already accumulated; for this purpose the explosive capacity` of the re damp mixture is eliminated by slowly burning the gases inV a specific apparatus.

The invention is by way of example illustrated in Fig. l of the attached drawing; Figure 2 shows a constructional detail thereof.

As apparent from the` drawing, the airis from the lower mine level sucked by the ventilator 2 into a funnel 1 located directly above the mine level and is conducted through tube 4 and rubber hose 481 to the slide contacts 5.

lf the air contains CH4 the sucked-in air may also be conducted through the combustion chamber 3, which may be sealed-olf by protective plate assemblies 3a.

The air leaving the combustion chamber 3 may also be conducted through a four-way cock 9 :and tube 4' to the contact places between` rail 10 and wheel 11.

Steam may also be conducted through tube 4 from an electrically heated steam generator 8 to the slide contact 5.

The` air-steam mixture may` also pass through fourway cock 9 and tube 4b to the contact places of rail 10 andI wheels 11. By an adjustment of four-way cock 9 only steam may be conducted` to the slide contact S and the contact places between the rail andthe wheels.

Fig. 2 illustrates on an enlarged scale the slide contact 5 located next to the overhead wire 7 the: contact being located within a downwardly open trough-shaped cover 6.

As` apparent from the drawings, the air conducted to the slide contact is sucked bythe ventilator and` flows on its way to the slide` contact to an electrically heated combustion chamber. In order to accelerate the decomposition of CH4, if present, the chamber mayl be provided with a suitable contact material.

In order to eliminate fire damp ignition in the combustion chamber the latter may be sealed olf by a tire damp protector, for instance, a series of wire nets or of protective plates. The CH4 is by the sucked-in air converted in the combustion chamber into CO2 and H2O. If the temperature in the combustion chamber is suitrice ' ably controlled formaldehyde may be produced, the presence of which is immediately noticed by its penetrating smell; this smell, therefore, is a reliable indicater for the presence of fire damp containing air mixture.

The combustion chamber may be replaced by a small electrically heated steam boiler, which supplies to the air sucked from the lower level of the mine suiiicient steam to prevent the ignition of the tire damp mixture. It may, however, be advisable in certain cases to only supply steam to the contact brushes.

Since certain changes may be made in the above article and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, what l claim as new and desire to be secured by LettersI Patent, is as follows:

1. Apparatus for the prevention of re damp explosion in an electric locomotive supplied by an overhead wire through an electric take-off mounted on top of the locomotive comprising, in combination, a conduit mounted on said locomotive and having an inlet opening near the bottom of the locomotive for drawing in a non-combustible mixture of air and an outlet opening adjacent the overhead wire at the electric take-olf; and means for drawing the non-combustible mixture of air into said inlet opening and discharging the mixture under pressure from the outlet opening of said conduit whereby the air discharged from said outlet opening removes any fire damp from the area of said electric take-off so that any sparks caused by the movement of the electric take-off along the overhead wire are prevented from igniting the lire damp.

2. Apparatus for the prevention of re damp explosion in an electric locomotive supplied by an overhead wire through an electric take-oit mounted on top of the locomotive comprising, in combination, a conduit mounted on said locomotive and having an inlet opening near the bottom of the locomotive for drawing in a non-combustible mixture of air and an outlet opening adjacent the overhead wire at theelectric take-01T; means for drawing the non-combustible mixture of air into said inlet opening and discharging the mixture under pressure from the outlet opening of said conduit; and a combustion chamber mounted in series with said conduit between its inlet and its outlet opening for removing any trace of CH4 present in the drawn-in mixture whereby the air discharged from said outlet opening removes any tire damp from the area of said electric take-off so that any sparks caused by the movement of the electric take-olf along the overhead wire are prevented from igniting the fire damp.

3. Apparatus for the prevention of iire damp explosion in an electric locomotive supplied by an overhead wire through an electric take-off mounted on top of the locomotive comprising, in combination, a stop cock mounted on said locomotive and having a plurality of outlets; a first conduit mounted on said locomotive and having an inlet opening at one of its ends near the bottom of the locomotive for drawing in a non-combustible mixture of air and terminating at its other end in said stop cock; a plurality of second conduits mounted on said locomotive, each of said second conduits being connected at one of its respective ends to one of the outlets of said stop cock, respectively and terminating at the other of its respective ends in an area desired to be re damp free; and means for drawing the non-combustible air into said inlet opening of said first conduit, transmitting the mixture through said stop cock and discharging the same under pressure from the other ends of said plurality of second conduits whereby the air discharged from the conduit ends removes any lire damp from the desired area so that any sparks caused by the movement of the electric locomotive are prevented from igniting the re damp.

4. Apparatus for the prevention of fire damp explosion in an electric locomotive supplied by an overhead wire through an electric take-olf mounted on top of the locomotive comprising, in combination, a stop cock mounted on said locomotive and having a plurality of outlets; a first conduit mounted on said locomotive and having an inlet opening at one of its ends near the bottom of the locomotive for drawing in a non-combustible mixture of air and terminating at its other end in said stop cock; a plurality of second conduits mounted on said locomotive, each of said second conduits being connected at one of its respective ends to one of the outlets of said stop cock, respectively and terminating at the other of its respective ends in an area desired to be iire damp free; means for drawing the non-combustible air into said inlet opening of said first conduit, transmitting the mixture through said stop cock and discharging the same under pressure from the other ends of said plurality of second conduits; and a combustion chamber mounted in series with said rst conduit between its inlet opening and said stop cock for removing any trace of CH4 present in the drawn-in mixture whereby the air discharged from the conduit ends removes any re damp from the desired area so that any sparks caused by the movement of the electric locomotive are prevented from igniting the ire damp.

References Cited in the le of this patent UNITED STATES PATENTS 893,878 Shires July 21, 1908 

